Dendrite growth and grain 'coarsening' in an undercooled CoNi equiatomic alloy
| Autor: | Yachan Zhang, Xian-Zong Wang, Hongxing Wu, Yiming Zhao, Haifeng Wang, Dexu Cui, Qing Zhou, Fan Zhang, Jianbao Zhang |
|---|---|
| Rok vydání: | 2020 |
| Předmět: |
Diffraction
Work (thermodynamics) Materials science Condensed matter physics Mechanical Engineering Alloy Metals and Alloys 02 engineering and technology engineering.material 010402 general chemistry 021001 nanoscience & nanotechnology Microstructure 01 natural sciences Power law Grain size 0104 chemical sciences Stress (mechanics) Mechanics of Materials Materials Chemistry engineering 0210 nano-technology Supercooling |
| Zdroj: | Journal of Alloys and Compounds. 816:152529 |
| ISSN: | 0925-8388 |
| DOI: | 10.1016/j.jallcom.2019.152529 |
| Popis: | The CoNi equiatomic alloy was undercooled and spontaneously solidified using the glass fluxing method. The dendrite growth behaviors were recorded by a high-speed high-resolution camera. Three dendrite growth stages (i.e., the power law growth stage when undercooling ΔT 135 K) were found and well predicted by a dendrite growth model. For the as-solidified microstructures, the average grain size increases with undercooling, indicating that unique grain “coarsening” instead of common spontaneous grain refinement occurs. Such a grain “coarsening” phenomenon was ascribed to stress accumulation upon rapid solidification. Furthermore, a plenty of sub-grains were observed within the abnormal coarse grains. From the electron back-scattering diffraction results, the angle difference between neighbouring sub-grains was less than 6°. The current work might be helpful for not only theoretically understanding dendrite growth but also practically controlling the non-equilibrium microstructures. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|
Full Text from ScienceDirect